The present invention relates to a vehicle drive apparatus that has a hydraulically operated speed change mechanism, is connected to an engine for use, and further has an electric oil pump for generating an oil pressure to be supplied to the speed change mechanism.
In recent years, in order to reduce fuel consumption and exhaust gas emission, an increasing number of vehicles have an idling stop function for stopping an engine when the vehicle is stopped. Moreover, hybrid vehicles using an engine and a rotating electrical machine as a driving force source typically have a function to stop an engine when the vehicle is stopped or decelerated. However, in vehicles having a hydraulically operated speed change mechanism, a mechanical pump, which is driven by the engine, is also stopped when the engine is stopped. In this case, oil pressure supply to the speed change mechanism is stopped, and the speed change mechanism cannot be operated properly. Thus, in a known structure, an electric oil pump is provided as an auxiliary pump in addition to the mechanical pump, so that an oil pressure generated by the electric oil pump is supplied to the speed change mechanism while the engine is stopped.
Since it is usually difficult to dispose such an electric oil pump inside a vehicle drive apparatus, the electric oil pump is often attached in contact with the outside of a case of a vehicle drive apparatus. For example, in an apparatus of Japanese Patent Application Publication No. JP-A-2003-56681 (paragraphs [0019]-[0021], FIG. 1), an electric oil pump is attached to an outer side surface of a transmission, more specifically, to an outer side surface of a transmission case at a position corresponding to an engine driven mechanical oil pump disposed in the transmission case.